The present invention relates generally to an apparatus for positioning tape to and from a printing apparatus, and more particularly to a tape positioning apparatus for use in a mailing machine in which tape is selectively moved to and from a printing position in which postage indicia is printed on the tape when the mailing machine is not printing the postage indicia on discrete envelopes. Modern day mailing machines, such as that shown and described in the aforementioned U.S. Pat. No. 4,922,085, have evolved into highly sophisticated, multi-functional machines capable of processing a plurality of mail pieces of different types through the steps required to affix proper postage to them for handling by the U.S. Postal Service. For example, the mailing machine just mentioned can store a plurality of mail pieces in a hopper, successively feed them seriatim to a weighing module which electronically determines the amount or postage required for each mail piece, print that amount of postage as an indicia either directly on the mail piece if it is relatively thin, such as a typical letter envelope or on a strip of tape which is applied to the envelope if it is too thick to feed through the printing mechanism, and finally deposit mail pieces in an orderly fashion in any of a variety of stacking devices for retrieval and further handling by Postal Service representatives. It should also be noted that the foregoing process occurs at a high rate of speed, usually in the order of 2 per second if weighing each piece is involved, 4 per second if weighing is not involved. Thus, it will be apparent that to accomplish this process at the indicated speed, the mailing machine requires a great number of mechanical parts which must fit together accurately and operate smoothly, and a highly complex electronic control system including various operator controlled devices and modules for setting up and operating the mailing machine, microprocessors for controlling the synchronous operation of various components and devices, and diagnostic systems for detecting various malfunctions and providing appropriate indication thereof.
In the mailing machine under consideration, a strip of tape of indefinite length is stored in a tape storage apparatus which is located adjacent the envelope output end of the mailing machine, in a position laterally offset from the longitudinal path of envelopes as they are fed through the mailing machine. The reason for this is that the mailing machine incorporates a postage meter module which has a flat bed type of printing device for applying postage indicia either to the envelopes as they are fed through the mailing machine or to a discrete portion of the strip of tape, depending on whether the mailing machine is in an envelope printing mode or a tape printing mode, the modes being under the control of an operator of the mailing machine. In the former mode, as envelopes are fed through the mailing machine by suitable feeding devices, an appropriate postage indicia is printed on the envelope in the proper location by the printing device which includes a movable element for raising the envelope to bring it into contact with a fixed printing die. In the latter mode, a mechanism must be provided for performing the same operation on the strip of tape to bring a discrete portion thereof into contact with the stationary printing die.
It is apparent, therefore, that the mailing machine has but one printing position, which is defined by the location of the printing die within the postage meter module of the mailing machine. Since far more regular envelope mail is processed through the mailing machine than oversized or over thick envelopes which cannot be processed through the normal envelope printing operation, the postage meter module is positioned in the mailing machine such that the postage indicia printing die is disposed in lateral alignment with the longitudinal path of the portion of the envelopes on which the postage indicia is printed. Thus, in order to print postage indicia on the strip of tape, it must be moved from the aforementioned offset position to a position in which the tape is laterally aligned with the printing die. The present invention hereinafter described and illustrated is directed to the apparatus for moving the tape back and forth between the offset position and the aligned position.
One of the requirements of the mailing machine under consideration is that of providing a tape positioning apparatus which can shuttle the tape between the aforementioned positions at a high rate of speed and with precise accuracy in the respective positions. Since the mailing machine operates at a high rate of speed in terms of the number of mail pieces processed as mentioned above, it is necessary that the tape positioning apparatus move between the offset and aligned positions not only with great speed but with very precise accuracy so that the tape is fed through the mailing machine smoothly and without interruption. The principal problem that occurs in alternate tape positioning as in the mailing machine under consideration is that of ensuring that the tape will feed smoothly and without jamming consistently and at a high rate of speed. After the postage indicia is printed on the strip of tape, the strip is fed in a forward direction to bring the trailing edge of the printed portion of the strip into alignment with a cutting device which severs the printed portion of the tape from the rest of the strip. Thereafter, the severed portion is fed through a delivery mechanism to a suitable location for retrieval by the operator of the mailing machine, while at the same time the strip of tape is fed in a reverse direction to bring the discrete portion of the tape on which printing will take place into the proper position for the next printing cycle on the tape.
Within the printing area of the mailing machine, the portion of the tape on which printing takes place is held in an elongate chute which shuttles that portion of the tape back and forth between the aforementioned offset and aligned positions. It was found, during the early stages of the design and development of the present invention, that the chute carrying the tape would not always return to the precise offset position from which it started at the beginning of a printing cycle, with the result that the leading edge of the strip of tape would not move smoothly from the outlet end of the chute past the cutting device and into the inlet end of the delivery mechanism. The downstream end of the chute would stop in a position in which it was slightly misaligned with the upstream end of the delivery mechanism, as a result of which the leading edge of the tape would snag on some portion of the structure defining the inlet end of the delivery mechanism and would jam in this position. Each time a jam occurred, the jam sensing mechanism would stop the mailing machine until the jam was cleared, which required that certain portions of the mailing machine not normally accessible to an operator had to be opened to permit an operator to clear the jam, thereby causing considerable down time. It is quite obvious that such a condition would be completely unacceptable in a high speed mailing machine.
In the course of further design and development of the present invention, other different design approaches were considered for an apparatus which would provide the necessary feeding characteristics of the tape. One in particular, which was a magnet mounted on the frame of the mailing machine to hold the downstream end of the chute in place, provided some degree of success at solving the foregoing problem, but not with the degree of accuracy required to provide the consistently smooth operation of the tape that was deemed necessary. It was not until the advent of the present invention that the feeding problem was considered satisfactorily solved in terms of providing a viable product.